I've had my Dual Boulder for a little over 2 years now, and I'm actually not sure when this started happening, but I wanted to check in and see if this is an indicator of a problem. Lately I've noticed that I can't seem to get anything past 9 bars of pressure. It usually hovers around 8 but doesn't often go past 8.5. This is different from when I got the machine - it easily reached 9 or 10 bars depending on the grind.
I've obviously tried adding more grounds, using a finer grind, or tamping harder, however the machine will choke below the 9 bar point, usually around the 8.5 mark. This is all with the single wall 2 shot portafilter - I've never used any of the others.
I've been using the same variety of beans for the last few years. (I find something I like and stick to it!) Either Fratello Godfather, or the Deville house blend sold there (roasted by Rosso). These are locally roasted and very fresh beans.
My grinder is the breville smart grinder pro. I'm on my second one, so I'm not sure the grinder has anything to do with the pressure issue.
I tried using a blind basket and running a clean cycle, and the machine just barely touches the 9 bar line.
The machine was in a couple of times (the latest trip was quite recent) for a steam wand leak, and they fixed that but I've noticed the pressure thing is still happening. Maybe it's normal for the pressure to reduce with years of use?
Please let me know what you think! =) Thanks.